Patients with HIV-disease have responded well to the highly activated antiretroviral therapy (HAART). However, our research group and others have shown that vision loss continues to occur despite elevated CD4 counts. In this grant we plan to assess and quantify retinal damage to the retinal nerve fiber layer (RNFL) and normal retinal tissue with the help of two non-invasive imaging techniques - scanning laser polarimetry (SLP) and optical coherence tomography (OCT). We will test two different hypotheses that might explain the vision loss - one is cytokine mediated optic neuropathy and the other is microvascular ischemia in the retina. The first specific aim of our study is to quantify RNFL defects by SLP, conventional OCT and high-resolution (HR) OCT in a cross-sectional and longitudinal study. RNFL defects are measured along a circumference around the optic nerve head in a manner analogous to studies in glaucoma research. The second specific aim is to quantify retinal defects throughout the posterior pole by HR-OCT in a cross-sectional and longitudinal study, as well. These retinal defects can occur throughout the retina and will be imaged by 3-D images. The third specific aim is correlate the RNFL and retinal defects detected with both imaging instruments with standard visual field function testing, short-wavelength automated perimetry and other structural and function data. Our research team encompasses a group of highly-qualified individuals with various expertise. Our team includes experts on retinal imaging, an expert in the study of HIV-related ocular complications, an expert in neurobehavioral research, and an expert on high-resolution optical coherence tomography.